1. Field of the Invention
The present invention relates to a lattice, preferably a metal lattice, which is obtained by stretching a blank or strip, preferably a sheet metal blank or sheet metal strip, which has been provided with rows of slits. The lattice has rhomboid or rhomboidal openings which are bordered by webs which extend obliquely relative to the plane of the lattice. The longer or major diagonals of the openings include an acute angle with the edge or border of the lattice.
2. Description of the Prior Art
Lattices of the above-described type are already known from German Utility Model No. 1,773,197. Compared to other known lattices in which the longer diagonals of the rhomboid or rhomboidal openings extend parallel to the edge of the lattice, the lattices of the type disclosed in German Utility Model No. 1,773,197 have the advantage that they have approximately the same bending strength in longitudinal direction and in transverse direction. Therefore, in practical use, these lattices are structurally relatively stable.
However, the lattices of the type disclosed in German Utility Model No. 1,773,197 as well as the other known lattices have in common a deficiency which is due to the fact that all edges or borders of the lattices are wave-shaped or are interrupted at a plurality of locations, because the webs which border the openings include over the major portion of their lengths an acute angle with the edges of the lattices.
The interrupted or wave-like shape of all edges of the known lattices reduces the usefulness of these lattices. The relatively sharp edges at the borders of the lattices mean that there is a danger of injury to the person handling the lattices. In addition, in certain types of applications of the lattices, it is unavoidable that at least some of the edges or borders of the lattices must subsequently be equipped with rectilinear border strips.
These border strips are particularly required if the lattices are to be used as so-called accumulator lattices.
It is, therefore, the primary object of the present invention to provide a lattice of the above-described type which, after the stretching procedure has been carried out, is not wave-shaped or toothed at at least two parallel edges of the lattice.